<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>demo 2-34</title>
	</head>
	<body>
	</body>
	<script>
		function test1(a){
			arguments[0] = 34;
			console.log(a);
		}
		function test2(a){
			"use strict";
			arguments[0] = 34;
			console.log(a);
		}
		function test3(a,b = 10){
			"use strict";
		};
		test1(20);
		test2(20);
		test3(5);
	</script>
</html>